1. Field of the Invention
The invention relates to child seat restraints for automotive vehicles and, in particular, to a latch restraint and anchorage system for securing the child restraint seat to the seat of a vehicle.
2. Background Art
Child safety seats have been required for many years by law for small children riding in automotive vehicles. In the past, child safety seats have been secured to a passenger seat using standard seatbelts provided for adult passengers that are anchored to one or more structural members of the vehicle. The seatbelts are normally threaded through apertures or slots provided in the child safety seat secure the child safety seat in position on the vehicle seat. The child safety seat mounting procedure is awkward and sometimes complex, which may result in improper securement of the child safety seat to the seat of the vehicle.
To overcome these problems, various regulations have been implemented requiring a standardization of the structure and methods for securing the child safety seat in an automotive vehicle. A recent Federal Motor Vehicle Safety Standard (FMVSS) adopted by the National Highway Traffic Safety Administration (NHTSA) requires vehicles be equipped with child seat restraint anchorage systems. The child restraint anchorage system outlined in this standard, FMVSS 225, requires, in part, that lower anchorages (i.e., latch wires) be rigidly attached to the vehicle, preferably one on each side of the child seat.
U.S. Pat. No. 6,276,754 issued to Youssef-Agha, et al. discloses a child safety seat having a pair of latch mechanisms which lockingly engage the latch wires to secure the child safety seat in position on the seat of the vehicle. The Youssef-Agha child safety seat includes latch wires that are welded to a cross member. However, welding distorts position and alignment of the latch wires. In other known anchorage systems for supporting and positioning the latch wires, bent legs of each latch wire are passed through enlarged holes provided in the cross member and then secured by a weld. The enlarged openings reduce rigidity relied upon for support, positioning and alignment, and make the assembly more susceptible to deformation due to welding heat.
Still other known anchorage systems for supporting and positioning the latch wires avoid the heat of a welding operation by providing a pair of collars on each latch wire leg. The legs are inserted into a cross member up to a first collar. A second collar is formed from the portion of the legs inserted into the cross member which protrude to the other side securing the latch wire to the cross member. This arrangement also avoids the need for an enlarged opening in the cross member to insert the legs through, since the legs in this instance can be straight. However, this arrangement does not resist deformation of the latch wire caused by use or abuse of the child safety seat as much as may be necessary.
Section S9.1 of FMVSS 225 requires the latch wire to include a transverse latch bar having approximately a 6 mm diameter. Child safety seat latch mechanisms are designed to engage the transverse latch bar of the latch wire. The standard 6 mm diameter allows child safety seat manufacturers to produce standardized latch mechanisms better equipped to safely secure a child. Further, the strength of the lower anchorages are regulated by Section S9.4 of FMVSS 225. The standard recites the maximum allowable deflection when certain forces are applied to the latch wire.
Typically, during manufacturing, each latch wire is formed from a constant diameter wire form, cut and bent into its preferred shape, which generally resembles the letter “U”. The wire form is selected to ensure that the transverse latch bar portion of the latch wire maintains a constant 6 mm diameter. Thus, the remaining leg portions of the latch wire, which engage a cross member, are also approximately 6 mm in diameter. However, latch wires having such a constant diameter have difficulty meeting the requirements for maximum allowable deflection.
Previously known systems included a support bracket placed over the latch wire and secured to the cross member to reduce the cantilever effect of forces on the latch wire. The support bracket avoided misalignment and distortion of the latch wire in anchorage systems. However, this method is problematic in that it adds an additional component increasing both the cost and assembly required.